SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4feef08309df9b023ce113d3f42899c0e4e17679d2adc3c7c6bda2c8b684c27e' 
  AND token = 'TVTVqFXaUVfEUxwIVS3+sNb8lVLpIZUJTMCrk9WDDuI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}